In my experience, this really comes down to the scale and lifetime of the application.

For a simple form collection app or some form of system that performs a simple administration task, I have used the action sequence. I generally have something along the lines of:

my $action = $query->param('ACTION');

unless(defined($action))
{
 $action = 'default';
}
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and then my if else based tree. For example, I have written small apps that manage lookup tables for databases where the data they contain is less than 20 rows in size. Adding a confirmation screen then becomes:

if($action eq 'delete')
{
 $confirmed = $query->param('CONFIRMED')
 if($confirmed eq 'yes')
 {
  # do stuff
 }
 else
 {
  # do other stuff
 }
}
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I find that this enables me to also port my code. Sadly, my new job involves some ASP programming (sigh) and have ported this technique to the small apps I have written there.

However, if your application will not allow a simple if-else tree followed with a simple confirmed -yes-no stage then pathinfo is my recommendation.So I will be keeping an eye out for the groupware book to see if I can pinch any ideas for my next large program.

But to continue the discussion, my last big app involved datadumping a hash into the form (after encrypting and mime encoding it) which proved a simple way of passing state information rather than parsing out a huge munge of hidden fields.

Could this be extended to tie the hash to disk instead and use a key on the form as the lookup to that tied file?